What it is: A maximum-strength teeth-whitening serum that delivers professional-level whitening with virtual zero sensitivity.What it does: The whitening serum combines potassium nitrate to help block teeth sensitivity and hydroxyapatite to help repair the enamel while whitening. Use the serum alone or for accelerated results, use with the brand's LED mouthpiece (sold separately). How to use: Start by brushing your teeth, and don't forget to floss and rinse. Apply the whitening serum by twisting the wand and covering the surface of each tooth you want to whiten. Keep on teeth for nine minutes and minimize swallowing. Once done, spit out any remaining serum and rinse. Use daily for up to three weeks at a time or until teeth whitening goals are achieved. 0.13 oz. Made in the USA